Underfeed stoker



Oct. 14, 1924.

A. H. BLACKBURN ET AL UNDERFEED sToKER 4 sheds-shew 2 Filed Nov. 1, V19,20

v l MAQZ Um" M w24' A. H. BLACKBURN ET AL 9 UNDERFEED STOKER Filed Nov. 1, 1920 4 Sheets-Sheet 'J MMWMAWM Oct. 14 1924. 1,5l1,442

A. H. BLACKBURN 'ET AL UNDERFEED STOKER 4 sheets-sheet 4 Filed Nov. 1, 1920 ufentor NNN @wwwwx l-mwxwx t? atented @ein le, 1924i,

Law

aan, e

.ARTHUR E. BLACKBURN, OF DETROIT, MICHIGAN, AND SAMUEL A. ARMSTRONG, OF SARNI, ONTARIO, CANADA, ASSIGNORS TO THE UNDERFEED STOK'ER COMPANY OE AMERICA, OF DETROIT, MICHIGAN, A CORPORATION Oil NEW JERSEY.

UNDERFEED STOKEE.

Application filed November 1, 1920. Serial No. 420,937.

To all whom t may concern:

Be it known that we,.AnTHUR lfl. BLACK-v BURN and SAMUEL A. ARMSTRONG, subjects of the King of Great Britain, residing, re-

spectively, at Detroit, in the county of lVayne, and State of Michigan, and at Sarnia, Ontario, Canada, have invented certain new and useful Improvements in Underfeed Stokers, of which the followingis a specification.

This invention relates to underfeedstokers of the lateral retort type, wherein a longitudinal, tuyerebordered-retort is supplemented by a plurality of laterally-extending tuyre-bordered retorts, which we refer to as branch retorts, the inner or receptive ends of which are disposed to receive their fuel supply from the main retort, suchtype of Stoker (we believe) having 2'@ originated with Klelfel Patent No. 1,270,171

granted June 18, 1918 and having been heretofore improved as shown in Armstrong and Blackburn Patent No. 1,333,696 granted March 16, 1920.

Its object is to improve such furnaces, particularly in the matters of feeding the fuel throughout the lateral or branch-retorts and in mechanical construction. 'To these ends it consists in the features of construction and combinations of parts hereinafter set forth and claimed.

In the drawings, Fig.. 1 is a front elevation of a furnace, stripped of its hopper; Fig. 2 is a plan-section on line 2--2 of F ig. 1; Fig. 3 is a cross-section on line 3-3 of Fig. 2, and F ig. l1 is a longitudinal section on line 4-4 of Fig. 1.

Between the furnace side-walls -10 the fire-box structure, extending from' frontwall 11 to bridge-wall 12, divides the combastion chamber or fire-box 13 above, from the wind-chamber 14- and ash-pits 15 below; said ioor in this particular construction, being made up of the retort-structure, deadplates and ash-dumpgates- F rom the fuel-hopper or magazine 16, centrally disposed outside of the front-wall, coal is fed by the ram 17, reciprocatingly drivenas by means of the usual steam-engine 18 (the frequency of whose operation is controlled by valve means not shown) through a throat 19 into and along a main, longitudinal retort 20. With this main retort communicate the inner or receptive ends of laterally-extending or branch retorts 21 that preferably are opposingly arranged in pairs on opposite sides of and at right angles to the main retort. We prefer` that the receptive ends of such lateral retorts shall be open throughout their crossfsectional area to the main retort, so that the sides of the main retort are left as a series of posts 22. r1`he braneh-retorts of each series along either side are separated suflieiently for their side walls to define air channels 23 below the floor, and these channels are spanned by tuyre-blocks 24. rthe tuyere blocks 2d that border the main retort crown 'the posts 22 and are preferably of mushroom shape, larger at their tops than at their bases, for increase of the area available for the tuyres and so as to restrict somewhat the mouths of the lateral-retorts close to the main retort for aid in securing effective distribution of fuel further out along the branch-retorts. Of course the tuyres direct the air under pressure, that is supplied in customary fashion to the wind-chamber, to `the fuel in the retorts.

The longitudinal main retort has its mouth preferably approximately horizontal and, preferably its bottom is also substantially horizontal to a oint beyond the rearmost lateral retort and) then is upsloped very steeply, so that the terminal resistance to longitudinal feed of the fuel may advantageously aid in the attainment of desired distribution through the lateral retorts. The laterally-extending or branch ret-orts have their mouths downsl'oped toward the furnace sides and have their bottoms upsloped to meet the mouths preferably on a gradual incline, the bottoms of opposing retorts of a pair, (as best shown in Fig. 3

being preferably struck on an arc of large radius that will pass. materially below the level of the bottom of the main retort. The laterally-extending or branch retorts, therefore, being deeper centrally than the main retort, cut through the latter, forming bottom channels or sub-channels 27 for uninterrupted transverse communication between opposed lateral retorts; or, otherwise stated, the bottom of the main retort has spaced openings to cross-channels 27 and these crosschannels communicate with the laterallyextending retorts, preferably by merging on a continuing curve, into the bottoms of the branch retorts.

The effect of thechanneling of the main retort is to tend to pocket or receive by gravit the lower stratum of ram-fed coal and divert some thereof into position to be easily fed to the branch retort.

Each communication channel or crosschannel 27, in the specific construction shown, has laterally reciprocating feeding means therein, shown specifically in the form of a feed blade 28 that preferably is slightly shallower than the channel depth and is appurtenant to a pusher bar 29 slidably mounted in the channel and preferably extending into the adjoining lateral retorts, such bar being curved on the arc of such lateralretort bottoms. Such bar referabl carries adjustable pusher bloc s 30 adjacent its ends these constituting feeding means in the opposlng lateral retorts. When reciprocated to carry the blade 28 first to one side and then to the other of the channel vcenter the bar with its attached blade 28 and blocks 3() will alternately feed coal to the opposed lateral retorts with positiveness and efficiency, insuring adequate and properly regulated supply of fuel clear to the end of leach branch and overcoming the tendency, that some sorts of coal manifest, to bridge over the operating areas of the lateral pushers in constructions such as that shown in Patent No. 1,333,696.

rl`he main retort is preferably provided with additional longitudinal feeding means, as a pusher rod 31, having thereon adjustable blocks 32, and operated from the feed ram in known manner as by the adjustable lost motion connection afforded by ram arm 33 working between adjustable pins 34 on the rod.

For driving the lateral feeding devices an independent engine 35 may be mounted on the boiler front to reciprocate a transverse rack 36, meshing with a sector 37 yon a shaft 39 and guided by a retainer hook 40 that is loosely mounted on the shaft and thathas lts upper edge inturned and channeled to fit over the rack. The shaft 39 carries, below the fire-box floor, gear sections 41 each meshing with a rack 42 that has a thin vertical web 43 extending through a slot 44 in the bottom of one of the channels 27, said web being secured to the feed bar 29 overlying the slot. Manifestly as the rack 36 is reciprocated the several feed bars 29 are recipFrocated also.

urther, in the4 specific construction shown, the improved mechanical construction provides, upon the foundation, longitudinal partition walls 46 supporting lengthwise beam structures 47, between which there extend the cross beams 48 that support the retort structure centrally and receive the hangers for the feed shaft 39. The retort structure is preferably made of a series of transverse, full-width castings, bolted together as at 21, each of the castings except the end ones including a pair of lateral branch retorts and two half-posts of the main retort, the end ones of the series of castings being modified as shown in Fig. 4, suitably to shape the ends of the structure. The side extremities of the retort structure bear on ianges of dead plates 50 that span between the beams 47 and parallel beams 51, bolted to cross beams 48, and beyond these dead plates, the dump-gates 52 are pivotally supported for dumping operation in known manner.

lin operation, the fuel is ram fed in quantities properly regulated by the periodicity of ram engine operation and the feed lengthwise of the main retort is additionally governed by the length of stroke of the main pusher rod 31 and adjustment of its blocks thereon, the abrupt bottom channeling of the retort receiving some of the'coal in the cross-channels to be fed into the bottom portion of the lateral-retort and the nearly vertical disposition of the rear end of the main retort causing the fuel to tend strongly to find its way into the laterallyextending or branch retorts. Feed along the latter is alternated as between the two series, or otherwise stated between thecopposi-ng retorts of each pair, by reciprocation of the channel contained blades 28, furthered by the adjustably positioned pusherl blocks 30. The independence of operation of these main and branch feeding devices gives a desirable facility of feed regulation. The fuel isthus delivered and massed throughout the large area of the retorts in such manner as to support efficient combustion according to best underfeed principles, and fuel consumption is usually substantially complete before the ash passes over the dead plates onto the dum ates.

W i e there is herein described a specific embodiment of my invention in considerable detail for full disclosure, it will be understood that many changes may be made in specific construction without departure from t e spirit of the invention within the scope of the appended claims.

We claim: A

1. In an underfeed furnace, the combination of a longitudinal main retort; lateral branch retorts on opposite sides of and opening into said main retort, having their bottoms lower at their inner ends than the bottom level of the main retort; said main retort having transverse channels in its bottom opening to and mergihg with the bottoms of opposed ones of said branch retorts; and feeding means arranged and adapted to feed fuel along said main retort.

2. In an underfeed furnace, the combination lof a longitudinal main retort; lateral branch retorts on opposite sides of and opening into said main retort, having their bottoms lower at their inner ends than the bottom level of the main retort; said main retort having transverse channels in its bottom opening to andmerging With the bottoms of opposed ones of said branch retorts; and feeding means arranged and adapted to feed fuel along said main retort, and other fuel feeding means arranged to feed fuel alongfeeding means arranged to feed fuel along' said transverse channels, the last said feeding means being operatable independently of the main retort feeding means.

.4. In an underfeed Stoker, the combination of a longitudinal main retort having in' its bottom transverse channels abruptly intersecting it, lateral branch retortson opposite sides of and opening into said main retort, these having their bottoms merging into the transverse channels of the main retort, a feeding ram for pushing fuel into one end of and along the main retort and transversely Working fuel feeding means in the channels.

5. In an underfeed Stoker, the combination of a longitudinal main retort having in its bottom transverse channels abruptly intersecting it, lateral branch retorts on opposite sides of and opening into said main retort, these having their bottoms merging into the transverse channels of the main retort, a feeding ram for pushing fuel into one end of and along the main retort and transversely Working fuel feeding means in the channels, each last said means comprising a central feed blade.

6. In an underfeed stoker, the combination of a longitudinal main retort having in its bottom transverse channels abruptly intersecting it, lateral branch retorts on opposite sides of and opening into said main retort, these having their bottoms merging into the transverse channels of the main retort, a feeding ram for pushing fuel into one end of and along the main retort and transversely Working fuel feeding means in the channels, each last said means comprising a central feed blade, a pusher bar extending into the adjacent branch retorts and pusher blocks on the bar.

7 In an underfeed-furnace, a' retort Structure .comprising a plurality of pairs of opposed lateral retorts, the retorts of each pair having their bottom portions in communication, and a main longitudinal retort between said opposed retorts and having its bottom above the level of the bottoms of said opposed retorts, the bottom portion of said longitudinal retort communicating With the bottom portions of said lateral retorts.

8. In an underfeed-furnace, a retort structure comprising opposed lateral branch retorts arranged in pairs and having substantially impervious bottoms, and a main longitudinal retort between said opposed retorts havin@r its bottom above the level of the bottoms of said opposed retorts, the bottom portions of the retorts of each pair communicating endvvise With each other, and the bottom portion of the main retort communicat-ing with the bottom portions of both of said retorts of each pair.

9. A retort-structure unit for underfeed furnaces, being a casting shaped to provide a pair of opposed lateral retorts and a portion of an interposed longitudinal retort, the bottom Wall of said unit affording the normal bottoms of the stated retorts andhaving a cross-channel portion that extends below the normal bottom of the main' retort portion and that connects With the bottoms of the lateral retorts.

10. In an underfeed furnace, a main longitudinal retort having a transversechannel in its bottom, a pair of lateral branch retorts opening to the main retort and having their bottoms meeting said channel in a continuing arcuate curve, said channel bottom being suitably curved and being slot-ted, feeding means for the branch retort pair including a bar overlying said slot and means for reciprocating said bar, extending through said slot.

11. In an underfeed furnace, a; main longitudinal retort having a transverse channel in its bottom, a pair of lateral branch retorts opening to the main retort and having their bottoms meeting said channel in a continuing arcuate curve, said channel bottom being suitably curved and being slotted, feeding means for the branch retont pair including a bar overlyin said slot, a blade centrally carried by sai bar, and means for reciprocating said bar, extending through said slot.

12. In an underfeed furnace, a main longitudinal retort having a transverse channel in its bottom, a pair of lateral branch retorts opening to the main retort and having their bottoms meeting said channel in a continuing arcuate curve, said channel bottom being suitably curved and being slotted, feedin means for the branch retort pair inclu ing a bar overlyin said slot, a blade centrally carried by sai bar, and pusher blocks near the ends of the bar, and

means for reciprocating said bar, extending through said slot. l

13. In an underfeed Stoker, a retort structure comprising opposed series of retorts arranged in a series of laterally extending pairs, the retorts of each pair spaced apart and having their bottoms in communication, and a main longitudinal retort having its bottom above the level of the bottom communications of the lateral retorts but with openings communicating therewith.

14. In an underfeed furnace, a retort structure comprising a main longitudinal retort, a series of'lateral retortsextending at an abrupt angle to the axis of the main retort, said main retort having, in its bottom, openings spaced correspondingly With the lateral retorts, and cross-channels leading froml these openings to the bottom portions of the respective lateral retorts.

15. In an underfeed furnace, a retort structure comprising a main longitudinal retort, a series-'of lateral retorts extending at an abrupt angle to the axis of the main l `retort, said main retort having, in its bottom, openings spaced correspondingly with the lateral retorts, and cross-channels leading from these openings to the bottom portions of the respective lateral retorts, feeding means for impelling fuel longitudinally into the main retort, and means or feeding fuel along the laterally-extending retorts.

16. In an underfeed stolzer, the combination of a longitudinal main retort having 'r bottom. openings at. intervals, cross-channels into which said openings permit fuel to fall from the main retort, a series of laterally extending retorts at each side of the main retort, opposed pairs of said lateral retorts being in communication through respective ones of said channels with the main retort, feeding means for forcing fuel into and along the main retort, and supplemental feeding means Working in said respective cross-channels for feeding fuel along the respective lateral retorts. i

17. In an underfeed Stoker, the combination of a longitudinal main retort having bottom openings at intervals, .cross-channels into Which said openings permit fuel to fall from the. main retort, a series -of laterally extending retorts at each side "ofthe main retort, opposed pairs of said lateral retorts being in communication through respective ones of said channels with the main retort, feeding means vfor forcing fuel into and along the main retort, and supplemental feeding means Working in said respective crosschannels for feeding fuel along the respective lateral retorts, and means loelovvy the bottoms of said retorts for Working the last said feeding means.

18. In an underfeed Stoker, a main retort extending from front to rear of the furnace, a set of lateral retorts located on each side of the main retort and extending crosswise of the furnace; communication passages connecting adjacent end-portions of opposed ones of said lateral retorts, said passages extending across, and below the level of, and opening to, the bottom of said main retort; and feeding means in each said coinmunication passage for feeding fuel from the main retort to the appropriate. lateral. retonts.

ARTHUR II. BLACKBURN. SAMUEL A. ARMSTRONG. 

